1. Field of the Invention
The disclosure generally relates to a mobile device, and more particularly, relates to a mobile device comprising two antennas.
2. Description of the Related Art
With the development of mobile communication devices, a variety of mobile communication devices have been introduced. Today, mobile communication devices may be classified into three types: smart phones, tablet computers, and notebook computers. In order to provide high transmission speeds for data and high quality images, the LTE (Long Term Evolution) standard has been developed for the next generation of mobile communication devices. The frequency range of the LTE is from the low frequency bands of 700 MHz to high frequency bands of 2690 MHz, and covers more than 10 application frequency bands. LTE communication systems are different from conventional 2G/3G communication systems, and they have specific application frequency bands for each country and location. Since the application frequency bands are not uniform, conventional portable LTE devices with a single design cannot be used all over the world.
It is very difficult to design a multi-band antenna which covers the LTE, 2G and 3G frequency bands, without increasing the size and complexity of today's mobile communication devices. When designing a multi-band antenna which covers the LTE, 2G and 3G frequency bands, at least seven frequency bands must be covered, which is difficult. Currently, a single antenna is used to cover several frequency bands. However, due to the techniques of achieving the LTE frequency, the performances of the 2G/3G frequency bands are degraded. Basically, mutual coupling between radiation elements of different frequency bands in the single antenna occur.